1. Field of the Invention
This invention concerns a vibration damping device, especially for a fan in a turbojet engine.
2. Description of the Prior Art
In some turbojet engines, the fan blades roots are mounted with play or slack inside axial dovetail slots distributed along the periphery of a support disk. At low speed, when the centrifugal force is inadequate to flatten the blade root onto the upper part of the slot, or on the ground when the fan is windmilling because of the wind, the blade roots rattle inside their slots. The rattling of the blade roots can lead to erosion of the protective rivets, a bruising of the disk notches or of the blade root and local corrosion, the above constituting deficiencies that can reduce the lifespan of parts and that can lead to the discarding of the latter, which is very expensive.
Various solutions have been put forth to remedy this deficiency which is common to all fans, such as the use of an elastic metal strip that is placed under the blade root, lining the casings under the blade platforms with synthetic foam or the use of inflatable bodies that can be placed beneath the platforms. However, those known methods do not completely remedy the above deficiencies.